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Why are forests
so important to Hawaii's water supply?
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The intimate relationship of Hawaii's forested
watersheds with its dependable supply of clean
water was recognized by the earliest Polynesian
settlers and continues today. An excerpt from a
1902 report by U.S. Forester E.M. Griffith on
Hawaiian forests states, "Forest protection
means not only increasing the rainfall but, more
important still, conserving the water supply. The
future welfare and agricultural prosperity of the
Hawaiian islands depends on the preservation of the
forest."
Forested watersheds perform four basic and
crucial functions. The first is that of an
umbrella. Tree leaves, branches, and understory
plants intercept rain before it reaches the ground.
This reduces the rain's erosive capacity and
increases the infiltration of the rain water into
the ground. Increased percolation (movement of
water through the soil) rates in forest soils
recharge underground aquifers, providing the supply
of artesian water. Stream flows are also more
consistent and cleaner, benefiting surface water
collection. Fog condensing on trees and other
vegetation is an important component of the water
resource. Fog interception in Hawaii can increase
total precipitation by as much as 30% of total
annual rainfall.
The second function forested watersheds perform is
that of a soil anchor. The roots of the trees and
associated plants grip the steep mountains
tenaciously, preventing soil from washing into the
ocean. This protects our ocean reefs and marine
life. Third, the forested watershed acts as a
sponge, soaking up rainfall into its soil, roots,
mosses, ferns, and leaves. When they are all fully
saturated, they slowly release water, thus
delivering a consistent and dependable source of
water for eventual use, long after the rain has
fallen.
The fourth function of a forested watershed is that
of a pump. Plants use water, which is released back
into the atmosphere through evaporation and
transpiration (or "evapotranspiration"). Both of
these processes are increased by warm and sunny
conditions. In the cooler temperatures and cloudy
conditions found in Hawaii's mountain watersheds,
evapotranspiration is greatly suppressed. This
allows much of the rainfall and condensed fog to
infiltrate into the ground, percolate through the
soil, and appear as clean water, either in streams
or ground water.
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How have people impacted Hawaii's
forested watersheds?
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Forests were the dominant vegetation on all the
main Hawaiian islands, especially on the mountain
slopes receiving moisture from the trade winds. By
the time of Captain James Cook's arrival in the
Hawaiian islands in 1778, the original forests,
especially in the lowlands, had been greatly
altered by over 1,000 years of intensive
agriculture and certain introduced plants and
animals brought by the Hawaiians. With European
contact, these impacts and changes accelerated
dramatically and spread into the mountain forests
with new agricultural and forest uses, increased
and population pressures, and the introduction of
more damaging plants and animals that multiplied
unchecked throughout the forests.
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When did Hawaii start a formal
program of protecting its forested watersheds?
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The earliest promulgation of laws in the
Hawaiian kingdom reflected the value of the natural
resources and the importance of management.
Building upon the ahupua'a land system, the laws of
the kingdom of Hawaii (May 3, 1841) tabooed certain
articles on the mountains, set up criteria for
harvesting forest products (especially large
trees), prohibited certain practices, and set up
penalties as incentives for people to obey those
laws. Public and private interests came together in
the late 1880's to make the needed investments to
assure a healthy and effectively managed forest
watershed. In 1892, a Bureau of Agriculture and
Forestry was established. The Hawaii legislature,
with support of the Hawaiian Sugar Planters'
Association, passed a bill in 1903 calling for a
Division of Forestry, which had the authority to
establish forest reserves for the protection of
springs, streams, and other water supply sources.
The first decade (1904-13) saw the establishment of
37 forest reserves totaling nearly 800,000 acres of
state and private land. A primary management goal
was the exclusion of livestock from the native
forests. Along with the fencing and elimination of
feral livestock came tree planting and fire control
programs. Reforestation began before 1900 in the
valleys behind Honolulu and reached a peak during
1934-41, when an average of nearly two million
introduced trees were planted annually in the
forest reserves. By the advent of World War II, the
forest reserve systems included 25% (1.2 million)
of the land area of Hawaii. Most severely eroding
areas had been reforested, and feral livestock
numbers were at manageable levels. Water was still
the most important product of the forest reserves,
but their potential to provide other benefits
became recognized
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What is the current condition of
Hawaii's forested watershed?
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Today, Hawaii has the 11th largest state-owned
forest and natural area reserve system (approx.
700,000 acres) in the United States. This is
augmented by a similar acreage of forest land in
private ownership, and an additional 150,000 acres
within federal jurisdiction (national parks,
national wildlife refuges, military training areas)
The forest reserves and much of the watershed
within the conservation districts are in good
hydrologic condition. Hawaii's long-standing policy
of watershed protection has resulted in dramatic
improvements from the degraded conditions that
prevailed at the turn of the century.
Although we are reaping the benefits of past
investments made in almost 100 years of successful
forest watershed management in Hawaii, we no longer
have a management program to assure we will have an
effective forest watershed for future generations.
Noxious weeds such as the dreaded Miconia,
are invading our mountain watersheds, which are
slowly degrading, and so is our water supply. With
the advent of federal and state species protection
legislation as well as increased recreational
demands, the State's budget for forestry and
watershed resource management is now spread over a
much larger set of issues. As a result, public
investment in watershed management has diminished
at the same time our community's demand for water
resources and attendant watershed values has
increased dramatically. Private landowners own half
of the remaining forested lands in Hawaii and there
are few incentives for them to invest in managing
their forested watershed.
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What are some of the other natural
resource and economic values that a healthy forest watershed
provide?
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The heart of many forested watersheds in Hawaii
are native rain forests and other native plant
communities, found nowhere else on earth. Each of
these Hawaiian species has value as a source of
unique genetic information, with possible medicinal
or other practical value to our society. Hawaii's
flora and fauna attracts researchers from around
the world and has become increasingly popular with
ecotourists. The native forest is also of great
cultural significnce as the home of plants and
animals important in Hawaiian culture and of
folklore and traditions based on ancient
relationships with the land. Hunting of feral pigs,
deer, and goats is a popular sport and source of
food for some of Hawaii's residents. While these
animals represent a valuable resource to the
hunting community, if left uncontrolled, can
seriously damage the watershed. Hiking, mountain
biking, fishing, photography, and nature study are
popular recreation activities in may of Hawaii's
watersheds.
In November 1997, a team of economists at the
University of Hawaii began a natural resource
valuation of the Koolau Mountains watershed on the
island of Oahu. Their preliminary economic analysis
of the amenities provided by the Koolau Mountains
watershed show an estimated Net Present Value (NPV)
of $7.44 to $14 billion. Amenities considered in
the analysis were ground water quantity, water
quality, in-stream uses, species habitat,
biodiversity, susbistence, hunting, aesthetics,
commercial harvests, ecotourism, and climate
control. NPV per acre was estimated at $76,000 to
$143,535 with a mean annual stream of benefits at
roughtly $165 million or $1,700 per acre. NPVs were
calculated using 3% and 1% social discount rates
for the ranges. Even without exploring Hawaii's
other forested watersheds in comparable depth, the
authors found prima facie reasons for concluding
that other forested watersheds around the State
would be at least as valuable as that of the Koolau
Mountains.
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What activities are involved
managing forested watersheds in Hawaii today?
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Watershed Resource Monitoring - A
baseline survey of the watershed condition and some
clear measure of the water quality and quantity
within the watershed is needed. Measures of forest
health and species diversity are also
essential.
Feral animal control - Feral animals
(escaped domestic animals) are a threat to many
watersheds in Hawaii. For millions of years, native
forests evolved without any need to develop
defenses (such as thorns or poisonous sap) against
grazing or browsing animals. Introduced pigs,
goats, cattle, and other hoofed animals have
destroyed large areas of forest cover the past 200
years. Control of feral animals in key watersheds
has been a priority of Hawaii's forestry program
since their inception in 1903. Today, in remote
regions where hunters seldom venture, damage is
continuing especially by feral pigs. In more
accessible regions, an aggressive public hunting
program can provide adequate watershed
protection.
Smaller animals also may become serious pests in
the watershed. Rats, feral cats and dogs, mice,
mongoose, and certain non-native birds are known to
destroy or compete with native species. East Maui
narrowly escaped an establishment of rabbits during
1989-91, when a careless pet owner released six
rabbits in Haleakala National Park. Without prompt
eradication, there is little question that rabbits
would have numbered in the millions in east Maui by
1994. Rats have become an increasing severe problem
in forested watersheds, not only impacting water
quality but native species as well.
Non-native weed control - Although
many beneficial non-native plants have been
introduced to Hawaii, a number of serious weeds
have also invaded native watersheds and threaten
their stability. Some weeds displace economically
or culturally important native plants, or convert
beautiful forest areas into impassable, thorny
tangles. Others promote wildlfire. Many weeds gain
a foothold in the forest by sprouting in areas
opened up by feral animals, spread by birds, or by
hikers or vehicles that enter the forest with mud
and seeds from other areas. One of the major
threats today is Miconia, which has taken
over 60% of Tahiti's rain forests, turning
multi-layered diverse native forests into single
species monocultures prone to land slides.
Incipient Miconia populations have been
cleared from Oahu and Kauai, but more aggressive
and sustained efforts are needed for Maui and
Hawii.
Control methods for weeds include manual pulling,
chemical treatment, and biological control (the use
of insects or diseases from the weed's homeland to
control the weed in Hawaii). For several species of
weeds, no effective control methods currently
exists for large infestations. It is important to
invest in measures to prevent additional noxious
weeds from becoming established in the first place,
and to support long-term research programs to
improve control methods.
Management infrastructure -
Management of forested watersheds requires a system
of suitable trails, roads, shelters, helicopter
landing sites and other basic infrastructure to
support the work of staff and the use of the area
by the public. These improvements must be designed
and maintained to minimize any unwanted impacts,
such as overuse of sensitive sites, inadvertent
introduction of weeds on hiker's boots or vehicles,
heightened liability exposure, increased potential
for damage to the water system, increased risk of
contamination of the water supply, or encouragement
of marijuana growing or other illegal
activities.
Public Education and Volunteer
Program - A program to build public
understanding and support for the management of the
watershed in the local community is needed.
Educational opportunities should be provided for
political leaders and interested citizen groups.
Special efforts are needed to communicate with
native gatherers and public hunters who have
traditionally used watershed areas. Volunteer
groups have proven successful in certain watershed
area management activities, especially in labor
intensive efforts such as fence construction, weed
control, and trail maintenance in accessible
areas.
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Why are watershed partnerships
important today?
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Watershed partnerships are the best approach to
manage large forested watersheds today in Hawaii
for several reasons:
- The entire watershed recharge area needs
protection and this requires the involvement of
all major landowners. Each part of the watershed
area is affected by the health of the
neighboring parcels.
- Even when combined, the resources of the
watershed partners are limited in relation to
what is needed to protect the entire watershed.
These limited resources must be carefully
managed in order to address the threats to the
watershed. A combined effort will take advantage
of economies of scale for large fencing projects
and other infrastructure needs. It will also
promote sharing of technical expertise to make
each partner more effective.
- Threats such as feral pigs and invasive
weeds do not respect parcel boundaries. By
working together, the partners will be more
effective in controlling these threats wherever
they occur.
- Success in large scale watershed projects
depend on community involvement and support.
Cooperation among the major landowners and a
clear plan for the watershed are prerequisites
for widespread community support. The planning
process also provide a forum for public
input.
The successful creation of the East Maui and
West Maui Mountains Watershed Partnerships have
reinvigorated the historic cooperative partnership
of public and private sectors in working together
to protect essential forested watershed recharge
areas in Hawaii. These partnerships encompass
over
100,000 acres of some of the best native rain
forests within the state. Over $1.5 million of new
monies have resulted from the development of these
partnerships.
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What other watershed partnerships
could be established in Hawaii?
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Other key watershed recharge areas that large
scale watershed partnerships could be applied
effectively include the Kohala Mountains and
Hualalai Mountains on the big island of Hawaii, the
Waianae Mountains on Oahu, South Maui, Lanaihale on
Lanai, and East/Central Molokai. Each partnership
will take a uniqure approach, largely driven by the
mix of landowners, the current status of the
watersheds, and the nature of the threats.
There are three key elements that need funding to
create watershed partnerships throughout the state.
They include:
- the establishment of new partnerships
(approx. $20-40,000 per area)
- the coordination of existing partnerships
(approx. $50-70,000 per County)
- the funding of management on the
ground.
One of the aspects of watershed partnerships is
that all partners agree to look for funding
sources, which helps leverage existing Federal,
State, county and private funds. Management
activities on the ground will vary according to the
size of the area and the activities needed. They
will tend to have higher initial costs for
infrastructure (fences, shelters, trails, helipads)
which could be considered capital improvements.
There will be lower costs for maintenance. For
example, the East Maui Watershed Partnership
(60,000 acres) needed about $1.2 million for
initial costs but long term maintenace will run
approximately $100-200,000.
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